Stainless steel enamel high temperature cobalt nickel underglaze without fluorinated salt and nitrate, its preparation method and application

Abstract

The application discloses a high-temperature cobalt-nickel underglaze for stainless steel enamel without fluorinated salt and nitrate, a preparation method and application thereof, and belongs to the technical field of enamel. The underglaze is composed of quartz, zero-water borax, titanium white, magnesium carbonate, potassium dihydrogen phosphate, soda ash, potassium carbonate, potassium feldspar, calcium carbonate, barium carbonate, iron oxide and recovered ternary battery positive electrode material according to specific mass ratio. The preparation comprises the steps of raw material mixing, high-temperature smelting under pure oxygen condition, wire drawing detection and rapid cooling and the like. The underglaze does not contain fluorinated salt and nitrate at all, avoids fluorine emission and environmental protection equipment blockage problems from the source, the fluorine content of the product is not detected through detection, meets the requirement of the EU REACH regulation, meanwhile, the underglaze has good enamel surface, luster and firing adaptability, is suitable for a stainless steel substrate, has a firing temperature of 840-880 DEG C and can be used for the production of green and environmentally-friendly enamel products.

Description

Technical Field

[0001] This invention belongs to the field of enamel technology, specifically relating to a high-temperature cobalt-nickel enamel base glaze for stainless steel that is free of fluoride salts and nitrates, its preparation method, and its application. Background Technology

[0002] High-temperature cobalt-nickel enamel base coats for stainless steel must simultaneously meet four core requirements: high gloss on the porcelain surface, an expansion coefficient matching that of stainless steel, good adhesion, and high-temperature firing (840-880℃). Traditional enamel base coat formulations typically include fluoride salts (such as fluorite and sodium fluorosilicate) (1-15%) as fluxes and adhesion enhancers. Fluoride salts are not optional additives in traditional enamel base coats, but rather indispensable structural components. Through multiple synergistic effects, such as lowering melting temperature, forming an alloy layer at the corrosion interface, creating a mechanical anchoring effect, and improving opacity and wettability, they lay the foundation for a strong bond between the enamel and the metal substrate from both physical and chemical dimensions. Simply and crudely removing fluoride salts is tantamount to removing the load-bearing walls of a building; the result is not a "degradation" of performance, but the "collapse" of the entire enamel system. Any attempt at fluoride-free enamel must be based on finding or inventing a new material or process system that can completely simulate or replace the aforementioned multiple functions, which remains a major technical challenge in the field of enamel technology. Therefore, the importance of fluoride salts in traditional processes cannot be overstated. However, research confirms that:

[0003] 1. Hydrogen fluoride (HF) and silicon tetrafluoride (SiF4) gases released during high-temperature melting cause harm to health and the environment.

[0004] 2. The EU REACH regulation lists fluorides as Substances of Very High Concern (SVHC). Fluoride salt products cannot meet the EU REACH regulations' requirements for fluoride, with a fluoride (F) limit of 20 mg / kg.

[0005] 3. The end-of-pipe environmental treatment equipment is blocked by fluoride crystals, which seriously restricts the normal production of enterprises.

[0006] Meanwhile, nitrates, as traditional oxidants and adhesion promoters, readily produce nitrogen oxides (NOx) during high-temperature decomposition. x Similarly, they also face environmental pressures. Currently, the removal of nitrates from enamel glazes has solved the problem of nitrogen oxide emissions (such as CN114368912B, CN114315150B, CN114315151B, etc.). Further achieving fluorine-free production and promoting the research and development of fluorine-free and nitrate-free systems is not only an inevitable choice to comply with regulations, but also a forward-looking technological layout for the future.

[0007] The replacement of fluoride salts is a major technological bottleneck at present, mainly reflected in:

[0008] (1) Fluoride salt dependence is strong, and environmental risk is prominent: CN119710693A (high-temperature-resistant enamel glaze) uses cryolite (Na3AlF6) as a fluxing agent, although it improves temperature resistance, but does not solve the problem of fluorine emission; CN112342544A (low-temperature acid and alkali-resistant cast iron enamel) contains sodium fluoride (5-7 parts) in the face glaze formula.

[0009] (2) Non-fluorine substitution scheme has functional defects: CN105800935A (enamel underglaze material) attempts to use lanthanide oxides to enhance adhesion, but it still needs to add 8% fluoride to assist melting, and the high cost of rare earths makes it difficult to promote. CN116854374A (black enamel composite glaze) uses a cobalt-nickel underglaze system, but the anti-explosive agent used contains 8-10% fluorite powder.

[0010] (3) The field of ceramics involves fluoride-free schemes, but it is difficult to apply: CN110885189A relates to a zirconium-free lanolin enamel and a positioning crystal flower ceramic tile made using the same, CN115626774A relates to a soft light skin ceramic rock plate and a method for preparing the same, CN112979271A relates to a method for preparing a light-weight high-strength pure-color glaze tile, and CN118754723A relates to a hydrophilic self-cleaning antique tile based on phase separation and a method for preparing the same. Although the above-mentioned prior art does not involve the use of fluoride salts, the technical essence belongs to the field of building ceramic glazes, which is different from the field of enamel underglaze. There are essential differences between ceramic glaze and metal-based enamel glaze in terms of thermal expansion coefficient (the difference in expansion coefficient between the two is one order of magnitude), firing temperature (the firing temperature of ceramic glaze is higher than that of enamel glaze by more than 200°C), and bonding mechanism (the body of ceramic glaze is porcelain clay, while the body of enamel glaze is metal), thus it cannot be directly applied to the field of metal-based enamel.

[0011] In summary, on the basis of denitrification, the problem of defluorination is solved, and the quality of enamel products is improved, which has very important practical significance for promoting the green, low-carbon, and high-quality development of the enamel industry. SUMMARY

[0012] In view of the excessive emission of fluorides in the production process of existing enamel glaze, which causes damage to health and the environment, the fluorine-containing salt products cannot meet the requirements of the EU REACH regulation on fluorine, and the emitted fluorine salt blocks environmental management facilities, seriously restricting the normal production of enterprises, the present invention provides a stainless steel enamel high-temperature cobalt-nickel underglaze without fluorine salt and nitrate, as well as a preparation method and application thereof.

[0013] The fluorine-free salt-free and nitrate-free stainless steel enamel high-temperature cobalt-nickel ground glaze of the application is composed of the following components in parts by mass: quartz 31-35 parts, zero-water borax 18-23 parts, titanium white 0.5-1 part, magnesium carbonate 0.5-2 parts, potassium dihydrogen phosphate 1-4 parts, soda ash 3-7 parts, potassium carbonate 1-4 parts, potassium feldspar 5-10 parts, calcium carbonate 8-12 parts, barium carbonate 5-10 parts, iron oxide 1-4 parts, and recycled ternary battery positive material 3.9-4.4 parts, wherein the recycled ternary battery positive material is a lithium, nickel, cobalt and manganese-containing powder material recovered from waste ternary lithium battery positive material.

[0014] Further, the fluorine-free salt-free and nitrate-free stainless steel enamel high-temperature cobalt-nickel ground glaze of the application is composed of the following components in parts by mass: quartz 31-35 parts, zero-water borax 18-23 parts, titanium white 0.5-1 part, magnesium carbonate 0.5-2 parts, potassium dihydrogen phosphate 1-4 parts, soda ash 3-7 parts, potassium carbonate 1-4 parts, potassium feldspar 5-10 parts, calcium carbonate 8-12 parts, barium carbonate 5-10 parts, iron oxide 1-4 parts, and recycled ternary battery positive material 3.9-4.4 parts, wherein the recycled ternary battery positive material is a lithium, nickel, cobalt and manganese-containing powder material recovered from waste ternary lithium battery positive material.

[0015] Further, in the quartz, the mass percentage of SiO2 and Fe2O3 is: SiO2≥99%, Fe2O3≤0.05%; in the potassium feldspar, the mass percentage of SiO2 and K2O+Na2O is: SiO2≥71%, K2O+Na2O≥11%; in the titanium white, the mass percentage of TiO2 is: TiO2≥99%; in the recycled ternary battery positive material, the mass percentage of Co, Ni, Mn and Li is: Co≥12.5wt%, Ni≥30.2wt%, Mn≥12.2wt%, Li≥5.9wt%; and the other raw materials are of industrial grade purity.

[0016] Further, the recycled ternary battery positive material is a commercially available material, which meets the above-mentioned percentage content of lithium, nickel, cobalt and manganese, and the other impurities contained therein do not affect the performance and use of the ground glaze.

[0017] The preparation method of the fluorine-free salt-free and nitrate-free stainless steel enamel high-temperature cobalt-nickel ground glaze comprises the following steps:

[0018] (1) The raw materials are weighed according to the above-mentioned mass parts;

[0019] (2) The raw materials in step (1) are stirred and mixed uniformly;

[0020] (3) The uniformly mixed material is added to a melting furnace, and melting is carried out under pure oxygen conditions, with the melting temperature controlled at 1300±10℃;

[0021] (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body is drilled, and is quickly drawn into a glass filament of 1.2-1.5 meters for detection, and the detection requirement is that no knot continues to melt for 2-5 minutes within 1 meter of the glass filament, and the melting is completed;

[0022] (5) the molten borosilicate glass body is rapidly cooled, and the product is obtained.

[0023] Further, in step (5), the rapid cooling is achieved by using a water quenching or tablet pressing process.

[0024] The application of the high-temperature cobalt-nickel underglaze enamel for stainless steel without fluorinated salt and nitrate is applied to a blank with a stainless steel base body, and the firing temperature of the finished product is 840-880 DEG C and does not include the end point value 840 DEG C.

[0025] The application introduces the recycled ternary battery positive material into the formula of the high-temperature cobalt-nickel underglaze enamel for stainless steel, so that the adhesion of the underglaze enamel is obviously enhanced, the synergistic effect between components is strengthened, and the promotion of the performance of the underglaze enamel surface, gloss and other performances is promoted.

[0026] The application has the following beneficial effects:

[0027] (1) fluorinated salt is discharged at an ultra-low standard;

[0028] (2) the product is detected by SGS, the fluorinated salt detection result shows that no fluorinated salt is detected, and the limit value requirement of SVHC (high concern substance) of the EU REACH regulation is met.

[0029] (3) the end environmental protection equipment blockage problem is solved: by completely removing fluorinated salt (fluorite, sodium fluorosilicate, etc.), the fluorinated salt crystallization source is eliminated from the source, and the end environmental protection equipment blockage problem is solved. According to the actual measurement of the production line, the continuous operation cycle of the equipment is prolonged from the original 10-15 days to more than 180 days, and the maintenance cost is significantly reduced.

[0030] (4) the core performance of the underglaze enamel is not attenuated: through the adhesion enhancement effect of the recycled ternary battery positive material instead of fluorinated salt, the adhesion level is 2-3 levels (the traditional high-temperature fluorinated underglaze enamel is 2-3 levels).

[0031] (5) good high-temperature firing adaptability: the eutectic composite fluxing system (multi-element carbonate + phosphate + borate) interacts with other components, so that the firing temperature is stably controlled at 840-880 DEG C, and the porcelain surface has good leveling property.

[0032] (6) the addition of phosphate and calcium carbonate provides [PO4] 3-The group promotes the nucleation of feldspar, the CaO / TiO2 reduces the viscosity of the liquid phase, accelerates ion diffusion, and the multi-component jointly acts to improve the expansion coefficient of the enamel, increase the adhesion of the enamel to the stainless steel and the gloss of the porcelain surface, and control the firing temperature of the enamel.

[0033] (7) Resource recycling and cost optimization: using recycled ternary battery positive electrode material, not only reduces the cost of cobalt-nickel-lithium raw materials by more than 25%, but also avoids heavy metal waste pollution. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The photo of the enamel plate made of stainless steel using the product obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0035] The present application will be further described in conjunction with specific examples, but the present application is not limited thereto.

[0036] The equipment used in the embodiment of the present application is as follows:

[0037] Batching: full-automatic batching and mixing system is adopted. The system is fully automatic computer controlled, and has the characteristics of accurate weighing, uniform mixing and high batching efficiency.

[0038] Melting: automatic feeding system, automatic pure oxygen combustion control system and automatic discharging system are adopted.

[0039] Packaging: automatic packaging system is adopted.

[0040] The purity of the raw materials used in the embodiment of the present application meets the requirements of industrial grade.

[0041] Example 1

[0042] (1) The raw materials are weighed according to the mass parts of each component as follows: quartz 31 parts, zero-water borax 23 parts, titanium dioxide 0.5 parts, magnesium carbonate 2 parts, potassium dihydrogen phosphate 1 part, soda ash 7 parts, potassium carbonate 1 part, potassium feldspar 5 parts, calcium carbonate 8 parts, barium carbonate 10 parts, iron oxide 4 parts, and recycled ternary battery positive electrode material 3.9 parts;

[0043] In the quartz, the mass percentage of SiO2 and Fe2O3 is: SiO2≥99%, Fe2O3≤0.05%; in the potassium feldspar, the mass percentage of SiO2 is ≥71%, and K2O+Na2O≥11%; in the titanium dioxide, the mass percentage of TiO2 is: TiO2≥99%; in the recycled ternary battery positive electrode material, the mass percentage of Co, Ni, Mn and Li in the total mass of the material is: Co≥12.5wt%, Ni≥30.2wt%, Mn≥12.2wt%, Li≥5.9wt%; and the other raw materials are of industrial purity.

[0044] (2) The above raw materials are stirred and mixed uniformly.

[0045] (3) the mixed material is added into a melting furnace, and melting is carried out under pure oxygen condition, and the melting temperature is controlled at 1300±10℃.

[0046] (4) after the above material is completely melted, a borosilicate glass body is obtained, the melted borosilicate glass body is drilled, and is quickly drawn into a glass filament of 1.2-1.5 meters for detection, and the detection requirement is that no knot exists in 1 meter of the glass filament, and the melting is continuously carried out for 5 minutes, and the melting is completed.

[0047] (5) the melted borosilicate glass body is rapidly cooled (water quenching), and the product is obtained.

[0048] The product obtained in example 1 is applied to a photo of a porcelain enamel plate made of stainless steel, as shown in Figure 1 The high-temperature cobalt bottom enamel of the stainless steel enamel without fluorinated salt and nitrate salt has a good porcelain surface, excellent high-temperature firing performance and adhesion performance, and is widely applied to the primary enamel product of stainless steel.

[0049] Example 2

[0050] The preparation process of the example is basically the same as that of example 1, and the difference lies in that:

[0051] In step (1), the mass parts of each component are: quartz 32 parts, zero-water borax 20 parts, titanium white 1 part, magnesium carbonate 0.5 part, potassium dihydrogen phosphate 4 parts, soda ash 5 parts, potassium carbonate 3 parts, potassium feldspar 6 parts, calcium carbonate 12 parts, barium carbonate 8 parts, iron oxide 1 part, and recycled ternary battery positive material 4.4 parts.

[0052] In step (5), the rapid cooling of the melted borosilicate glass body is carried out by using a tablet pressing process.

[0053] Example 3

[0054] The preparation process of the example is basically the same as that of example 1, and the difference lies in that:

[0055] In step (1), the mass parts of each component are: quartz 33 parts, zero-water borax 21 parts, titanium white 0.8 part, magnesium carbonate 1.5 part, potassium dihydrogen phosphate 3 part, soda ash 3 part, potassium carbonate 2 part, potassium feldspar 10 part, calcium carbonate 10 part, barium carbonate 7 part, iron oxide 2 part, and recycled ternary battery positive material 4.0 part.

[0056] Example 4

[0057] The preparation process of the example is basically the same as that of example 1, and the difference lies in that:

[0058] The mass parts of each component in step (1) are: quartz 35 parts, zero-water borax 18 parts, titanium white 0.5 parts, magnesium carbonate 2 parts, potassium dihydrogen phosphate 2 parts, soda ash 6 parts, potassium carbonate 4 parts, potassium feldspar 8 parts, calcium carbonate 8 parts, barium carbonate 5 parts, iron oxide 3 parts, and recovered ternary battery positive material 4.3 parts.

[0059] Comparative Example 1

[0060] The rest is the same as in Example 1, except that the mass parts of each component in step (1) are: quartz 32.0 parts, zero-water borax 22 parts, titanium oxide 0.8 parts, soda ash 3.30 parts, lithium carbonate 5.0 parts, barium carbonate 7.0 parts, fluorite 9.0 parts, potassium feldspar 13.0 parts, manganese oxide 0.6 parts, cobalt oxide 0.8 parts, nickel oxide 2.7 parts, and iron oxide 2.0 parts.

[0061] The test results of the products obtained in the above examples and comparative examples are shown in Table 1 below.

[0062] Table 1 Test results of products obtained in examples and comparative examples

[0063]

[0064] The above examples and test results prove that the stainless steel enamel high-temperature cobalt-nickel base glaze produced by the method of the present application does not contain fluorinated salts and nitrate salts, no fluorides are generated during the preparation process, and the properties of the obtained product (high brightness, high expansion coefficient, good adhesion, firing temperature, etc.) all meet the requirements of stainless steel enamel high-temperature cobalt-nickel base glaze. The fluorine detection result of the product shows that no fluorine is detected, which meets the limit requirements of SVHC (substance of very high concern) of the EU REACH regulation, and fundamentally solves the technical problems of existing stainless steel enamel high-temperature cobalt-nickel base glaze in the production process, such as fluorine gas emission polluting the environment and fluorinated salts emitted to block environmental protection treatment facilities.

Claims

1. A high temperature cobalt nickel underglaze for stainless steel enamel which is free of fluorinated salts and free of nitrates, characterized in that, The formula is composed of the following components in parts by mass: quartz 31-35 parts, zero-water borax 18-23 parts, titanium white 0.5-1 part, magnesium carbonate 0.5-2 parts, potassium dihydrogen phosphate 1-4 parts, soda ash 3-7 parts, potassium carbonate 1-4 parts, potassium feldspar 5-10 parts, calcium carbonate 8-12 parts, barium carbonate 5-10 parts, iron oxide 1-4 parts, and recycled ternary battery positive electrode material 3.9-4.4 parts, wherein the recycled ternary battery positive electrode material is a lithium, nickel, cobalt and manganese-containing powder material recovered from waste ternary lithium battery positive electrode material.

2. The fluorine-free salt-free nitrate-free stainless steel enamel high temperature cobalt nickel underglaze of claim 1, wherein, Quartz 33-35 parts, zero-water borax 18-21 parts, titanium white 0.5-0.8 parts, magnesium carbonate 1.5-2 parts, potassium dihydrogen phosphate 2-3 parts, soda ash 3-6 parts, potassium carbonate 2-4 parts, potassium feldspar 8-10 parts, calcium carbonate 8-10 parts, barium carbonate 5-7 parts, iron oxide 2-3 parts, and recycled ternary battery positive electrode material 4.0-4.3 parts.

3. The fluorine-free salt-free and nitrate-free stainless steel enamel high temperature cobalt nickel underglaze according to claim 1 or 2, characterized in that, In the recycled ternary battery positive electrode material, the mass percentage of metals in the total mass of the material is Co≥12.5wt%, Ni≥30.2wt%, Mn≥12.2wt%, and Li≥5.9wt%.

4. The fluorine-free salt-free nitrate-free stainless steel enamel high temperature cobalt nickel underglaze of claim 1 or 2, wherein, In the quartz, the mass percentage of SiO2 and Fe2O3 is SiO2≥99% and Fe2O3≤0.05%.

5. The fluorine-free salt-free and nitrate-free stainless steel enamel high temperature cobalt nickel underglaze of claim 1 or 2, wherein, In the potassium feldspar, the mass percentage of SiO2 and K2O+Na2O is SiO2≥71% and K2O+Na2O≥11%.

6. The fluorine-free salt-free and nitrate-free stainless steel enamel high temperature cobalt nickel underglaze of claim 1 or 2, wherein, In the titanium white, the mass percentage of TiO2 is TiO2≥99%.

7. A process for the production of a high temperature cobalt nickel underglaze for enamel of a stainless steel free of fluorinated salts and free of nitrates according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) weighing each component raw material; (2) stirring and mixing the raw materials in step (1) uniformly; (3) adding the uniformly mixed material into a melting furnace, and melting under pure oxygen condition, with the melting temperature controlled at 1300±10℃; (4) after the material in step (3) is completely melted, a borosilicate glass body is obtained, the molten borosilicate glass body is tapped, and is quickly drawn into a 1.2-1.5 meter glass filament for detection, with the detection requirement being that no knot is observed within 1 meter of the glass filament, and the melting is continued for 2-5 minutes to complete the melting; (5) rapidly cooling the melted borosilicate glass body to obtain the product.

8. The production method according to claim 7, wherein In step (5), the rapid cooling is achieved by water quenching or tablet pressing process.

9. Use of a fluorine-free salt-free and nitrate-free stainless steel enamel high temperature cobalt nickel underglaze according to any one of claims 1 to 6, characterized in that, The product is applied to a blank with a stainless steel base, and the firing temperature of the finished product is 840-880℃, and does not include the end point value 840℃.

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